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Toxicity Screening for Giardia duodenalis (IgG) – Serum

Published: August 9, 2026Updated: August 16, 2026

This test checks for antibodies in your blood that may indicate past exposure to the Giardia parasite, which causes intestinal infections often linked to contaminated water or poor hygiene.

Quick summary

["Helps identify past exposure to Giardia without confirming active infection."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
40786-6
Short code
T gondii IgG sp2 Titr Ser
Synonyms
T gondii IgG sp2 Titr Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What This Test Measures

Giardia duodenalis is a microscopic parasite that can infect your digestive system. After you’ve been exposed, your immune system produces antibodies (IgG) to fight it. This test detects those antibodies in your serum to see if your body has encountered the parasite before.

Why It’s Ordered

Your healthcare provider may recommend this test if you’ve had symptoms like stomach cramps, diarrhea, bloating, or nausea—especially after traveling to areas with poor sanitation or consuming untreated water. It’s also used in screening for travelers or individuals with recurrent digestive issues.

What to Expect Before the Test

No special preparation is needed. You’ll have a simple blood draw from a vein in your arm. The test is usually done in a lab and results are ready within a few days.

What the Results Mean

A positive result suggests your body has likely been exposed to Giardia in the past, but it doesn’t confirm an active infection. A negative result means no detectable antibodies were found, so further testing may be needed if symptoms persist.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Giardia IgG Antibody (Serum)

Frequently asked questions

Why was this test ordered?
Your doctor may have ordered this test to investigate symptoms like persistent diarrhea, abdominal pain, or nausea—especially if you’ve traveled to regions with known Giardia outbreaks or consumed potentially contaminated water. It helps differentiate between past exposure and active infection, guiding treatment decisions if needed.
What does a positive result mean?
A positive result indicates your immune system has produced antibodies against Giardia, meaning you’ve likely been exposed to the parasite at some point. However, this does not confirm an active infection. If you’re experiencing symptoms now, further testing (like a stool sample) may be required to check for current infection.
Can this test detect an active Giardia infection?
No, this test only detects antibodies (IgG) from past exposure. For an active infection, your doctor may order a stool test or other diagnostic procedures to identify Giardia parasites directly.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy